Abrasive and polishing head



May 10, 1949. A. P. BEAM l-:TAL

ABRASIVE AND POLISHING HEAD Filed Oct. 10, 1946 INVENToRs Arthur I? BeamHamly Raz/mond eam,

a H2. l ATTORN S Patented May 10, 1949 ABRASIVE AND POLISHING HEADArthur P. Beam and Harry Raymond Beam, Shelton, Conn.

Application October 10, 1946, Serial No. 702,408

1 claim. 1

This invention relates to abrasive and polishing disks or heads.

An object of the invention is to provide anl improved economical andlightweight abrasive or polishing head which is especially adapted foruniversal use with portable tools such as electric drills, poweredflexible shafts and the like, without requiring the use of tools,special fittings, adaptors, etc.

Another object of the invention is to provide an improved abrasive orpolishing head as above, which is extremely simple in construction, andeffective and reliable in use, and economical to manufacture.

A further object of the invention is to provide an abrasive or polishinghead in which the working element may be quickly and convenientlyremoved and replaced with a new element, when this is necessary.

A still further object of the invention is to provide an improvedabrasive head which mounts renewable abrasive disks in such a mannerthat a iiat abrasive surface devoid of protuberances or projections ispresented to the work, the said head being so organized that replacementof the abrasive disks may be quickly and conveniently carried out.

These objects are accomplished, according to` the invention, by theprovision of a novel head structure comprising a rotary metal supportingdisk having a dished central portion providing a. recess in its workingface, the said portion mounting a short stub spindle. The spindle is ofsuch size that it may be readily gripped in the chuck of an electricdrill, flexible shaft or the like, and therefore the headstructure isuniversally usable with such portable devices without requiring specialttings, tools, adaptors and the like.

The recess formed in the face of the disk carries a clamping collar orwasher which lies wholly below the disk surface, and which clamps anabrasive paper or cloth disk to the metal supporting disk without anyparts of the clamping device projecting beyond the disk face. Thus acompletely fiat abrasive surface is presented to the Work at all times,which is advantageous when finishing surfaces of car bodies and thelike.

The metal supporting disk is preferably of thin, exible and resilienthard sheet aluminum alloy.

We have found that when the disk is formed of the hard, tough andresilient alloy commonly ernployed in airplanes and in one form knowncommercially as Z4-ST, it may be quickly and economically fabricated bysimple forming and stamping operations which are few in number, withoutresorting to additional operations such as annealing, hardening andtempering, which add expense to the fabrication process, or withoutresorting to the use of more expensive metals such as spring bronze andsimilar alloys, which while not requiring annealing or tempering,represent a high material cost. By the use of a suitable aluminum alloy,the supporting disk may be made very thin and may be extremelylightweight, while at the same time possessing the required strength,toughness and flexibility to satisfactorily function for supporting androtating at high speed an abrasive or polishing element. As a result,any likelihood of the supporting disk sudering permanent deformation ordistortion during use is considerably minimized.

Due to its simplicity and few small parts, the entire assemblageincluding the stub spindle is of very light weight, especially adaptingit for use in portable tools, and is rugged in use.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Figure 1 is an edge elevation of the improved head structure of thepresent invention, applying a polishing element to a workpiece and beingcarried on an electric hand drill.

Fig. 2 is a rear elevation of the head structure, a peripheral portionof the polishing element being broken away and shown in section to moreclearly illustrate the structure.

Fig. 3 is a diametric section of the head structure and polishingelement taken on the line 3-3 of Fig. 2, and

Fig. 4 is a diametric section of the head structure mounting an abrasivedisk element.

Referring to Figs. /2 and 3, the abrasive or polishing elem'entsupporting head comprises a disk I0 which is of very thin andlightweight sheet metal, the said disk being preferably of the exibleand resilient hard aluminum alloy commonly used in aircrafts, and havinga laterally odset, dished center portion Il which is apertured toreceive the driving member for the disk.

As clearly shown in Fig. 3 the portion of the disk I0 surrounding thecentral offset is preferably slightly crowned, the front or working facebeing the convex side.

The disk l0 may be fabricated in various ways. y

manent distortion or deformation to a considerable degree, especiallywhen being rotated at high working speed. Heretofore supporting diskstructures were not formed of aluminum or its alloys for the reason thatit was thought the structure would not be strong enough to withstandsevere use. However, by employing the hard aluminum alloy known as Z4-STand comprising 4.4% copper, 0.5% manganese, 1.5% magnesium and balancealuminum, which has been specially adapted for aircraft use, or asimilar aluminum alloy which has considerable resiliency. toughness andhardness or resistance to bending, and by forming such metal in theshape shown with a central dished portion and a slight crown. anextremely practical, rotatable supporting head structure is obtainedwhich has the necessary strength for the purpose required, and is at thesame time extremely lightweight so that it is well adapted for use inportable tools. In addition, it is economical to fabricate, since thematerial cost is low as compared with the cost of the bronzes or carbonsteel. In the case of the latter material there is present the hardeningand tempering operations which of themselves add to the cost. Where ahardened steel disk is used as a supporting head structure, there isalways the likelihood of the steel cracking or breaking, whereas inaccordance with the present invention by the use of the aluminum alloyreferred to above, it is impossible for the disk to crack or breakduring usage.

According to the invention the disk I is provided with a stub shaft orspindle I2 having a shank I2a which is preferably smooth and is of suchsize and shape that it may be inserted and gripped in all types of drillchucks commonly employed with electric drills, powered flexible shafts,and the like. The stub shaft i2 has a threaded portion extending throughthe aperture in the disk I0 and carrying nuts I3 which between themsecurely clamp the center of the disk and support the latter forrotation.

4 periphery of the sheepskin disk I4, the said ring carrying adrawstring Il.

When the polishing disk I4 is applied over the supporting disk I0, theperipheral edge portion I9 the disk to have universal and widespread usewith existing equipment. In addition, transferring of the disk from oneportable tool to another does not involve disassembly of any of theparts of the disk, and the latter may therefore remain intact. It willbe seen that during the assembly of the stub shaft I2 to the disk IIJthe nuts I3 may be pulled up very tightly with suitable wrenches andsecured against loosening so that during usage, and in spite of severevibration, flexing of the disk etc., no failure will result due toloosening of threaded members as has been the case heretofore in priorsupporting disk structures.

As shown in Figs. l through 3, the disk I0 may carry a relatively thickfur-like polishing element I 4 of sheepskin; such elements, as is wellknown, have long woolen bres I5 emanating from a hide base I6. Thepolishing element Il is in the form of a disk having a diameter slightlygreater than that of the supporting disk I0, and a tubular cloth ring'Il is secured to and extends along the of the polishing disk will extendover the periphery of the supporting disk, and upon the drawstring I8being4 tightened and tied, the said peripheral portion I9 will be foldedover the thin bladelike periphery of the disk III and will tightlyembrace the latter on both sides thereof.

We have found that, this construction, together with the inherentnon-slip surface characteristics of the hide base I8, the polishingelement I4 is tightly secured to the supporting disk III againstslippage. Also, due to the toughness of the hide I6, the latter willresist abrasion from the bladelike periphery of the disk to aconsiderable extent, if for any reason, such as when the tie-string isnot tight enough, slippage should occur between the polishing elementand the disk.

A polishing head as made in accordance with this invention, when somounted on an electric hand drill or-other portable tool, provides aneffective, portable polishing device which may be conveniently appliedto a workpiece W as shown in Fig. 1, to brighten and polish the surfacethereof.

Due to the hardness or stiffness, and to the resiliency of thesupporting disk I0 and the speed at which the disk is drivenIconsiderable pressure may be applied during the polishing operationwithout resulting in permanent deformation of the disk. During theapplication of the polishing head to the workpiece W a slightdeformation of the disk may occur, as illustrated in Fig. 1, due to theunbalanced lateral pressure on the head. However, this deformation isnot permanent because of the resiliency of the supporting disk, and isin fact desirable in enabling the polishing head to conform to variousshapes and contours of workpieces.

Referring to Fig. 4 the supporting disk III may carry a centrally-apertured abrasive disk 20 of am' well-known type, the said abrasivedisk having either a paper or cloth foundation. The

abrasive disk 20 is clamped to the supporting disk I0 by means of adished frustro-conical clamping washer 2l which is secured under one ofthe clamping nuts I3. The construction is such that the nut I3 andclamping washer 2| are disposed wholly below the mouth of the dishedportion of the disk I0, and below the surface of the abrasive disk 20,and therefore there are no projecting or protruding parts which mightinterfere with the abrading of a large surface or area.

It will be seen that the center portion of the abrasive disk 20 isclamped under the peripheral edge portion of the washer 2l, and bysecurely tightening the nut I3 holding the washer, the entire innerperiphery of the abrasive disk is securely held in place and preventedfrom pulling out.

The supporting head structure of this invention is thus seen to beextremely simple in construction and economical to manufacture, and tobe quickly applicable to various types and sizes of portable tools. Whendesired, either the abrasive or the polishing element may be quickly andconveniently replaced, either while the supporting head is mounted onthe tool, or when the head is removed from the tool. Due to the aluminumalloy material used in forming the disk II) and due to the thinness andparticular shape and structure of the disk, the latter is of lightweight while at the `same time having considerable strength for thepurpose intended.

Variations and modifications may be made within the scope of thisinvention and portions of the improvements may be used without others.

We claim:

A supporting head for an abrasive or a polishing element, comprising alightweight, thin resilient stamped sheet metal disk of hard aluminumalloy consisting of 4.4% copper, 0.5% manganese, 1.5% magnesium, and93.6% aluminum, said disk having an annular working portion, and adrawn, dished center portion located within and close to said workingportion, and said disk being characterized by a total lack of heattreatment after its formation; and a stub driving spindle secured to andat one end passing through the center portion of the disk, said spindleextending axially from the disk and having a shank for insertion into adrill chuck to be gripped thereby, the end of the spindle within thedished portion of the disklying wholly below the mouth of said portion.

ARTHUR P. BEAM.

HARRY RAYMOND BEAM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

